Economic impact of decreasing the fraction number in vaginal cuff brachytherapy: A direct cost analysis

Are 7.5 Gy×2 fractions more efficient than 6 Gy×3 in exclusive postoperative endometrial cancer brachytherapy? A clinical and dosimetrical analysis

PURPOSE

To compare two vaginal brachytherapy (VBT) schedules in postoperative endometrial carcinoma (PEC) patients considering vaginal-cuff relapses (VCR), late toxicities, dosimetry analysis and vaginal dilator use.

MATERIAL AND METHODS

110 PEC patients were treated with exclusive high-dose-rate VBT using two schedules. Group-1:44-patients received 6 Gy×3fractions (September-2011-April-2014); Group-2:66-patients were treated with 7.5 Gy×2fractions with a dose limit of equivalent total doses in 2-Gy fr (EQD2(α/β=3)) of 68 Gy in the most exposed 2 cm3 of clinical target volume (CTV) (July-2015-November-2021). The dose was prescribed at 5 mm from the applicator surface. Were evaluated the overall radiation dose delivered to 90% of the CTV (D90), the CTV receiving 100% of the prescription dose (V100) and the EQD2(α/β=3) received in the most exposed 2 cm3 to dose in CTV. Late toxicity was prospectively assessed using RTOG scores for bladder and rectum and objective LENT-SOMA criteria for late vaginal toxicity (LVT).

STATISTICS

Descriptive analysis, Chi-square, Student's t-tests and Kaplan and Meier method.

RESULTS

The median follow-up was 60 months (15.9-60). There were no VCR or late toxicities in bladder or rectum. LVT ≥ G1 appeared in 26/44 (59.1%) in Group-1 and 25/66 (37.9%) in Group-2. The mean EQD2(α/β=3) received by the most exposed 2 cm3 of CTV was 63.7 Gy ± 10.0 in Group-1 and 60.5 Gy ± 3.8 in Group-2 (p = 0.063). There were no differences in adherence to vaginal dilator use ≥9 months, overall D90 and V100.

CONCLUSION

Considering the lack of vaginal relapses and similar LVT over time, 7.5 Gy×2fractions seem more efficient in terms of patient comfort, workload, and cost. This is the first study using dosimetry parameters to compare effectivity of schedules. Larger series are needed to confirm the present results.

The role for vaginal cuff brachytherapy boost after external beam radiation therapy in endometrial cancer

PURPOSE

To evaluate the role and technique of a vaginal cuff brachytherapy (VB) boost to adjuvant external beam (EB) radiation for endometrial cancer through a systematic review.

METHODS AND MATERIALS

Relevant trials were identified through a systematic search of the literature.

RESULTS

A total of 21 prospective and retrospective studies which had a patient cohort undergoing EB + VB was identified to evaluate for rates of vaginal and pelvic recurrences, overall survival, and toxicity. Additional database studies were utilized to demonstrate differences in local control and overall survival between EB and EB + VB.

CONCLUSIONS

While there is limited prospective evidence to guide the use of a VB boost after EB, the evidence suggests that patients with a higher risk of a vaginal recurrence such as those with cervical stromal involvement in select Stage III patients may derive local control and survival benefits from a VB boost. Additional individual risk factors such as grade, histology, extent of invasion, margin status, age, and the use of lower doses of EB should be considered when deciding when to add a VB boost.

Preliminary results of a vaginal constraint for reducing G2 late vaginal complications after postoperative brachytherapy in endometrial cancer: a prospective analysis

Purpose

To evaluate the preliminary results of the use of 68 Gy EQD2_{(α/β=3 Gy)} as a dose limit to the lowest dose in the most exposed 2 cm³ of the vagina in order to reduce G2 late vaginal problems in postoperative endometrial carcinoma (EC).

Methods

From November 2016 to October 2019, 69 postoperative EC patients receiving vaginal brachytherapy (VBT) ± external beam radiotherapy (EBRT) were prospectively analyzed. The median EBRT dose was 45 Gy (range: 44–50.4 Gy), 1.8−2 Gy/day, 5 fractions(Fr)/week. VBT was administered with the following schedule: 1Fr of 7 Gy after EBRT and 2 daily Fr × 7.5 Gy in exclusive VBT. The dose was prescribed at 0.5 cm from the applicator surface with an active length of 2.5 cm; 56 patients were treated with vaginal cylinders (49–3.5 cm, 6–3 cm, and 1–2.5 cm) and 13 with the colpostat technique. The overall VBT dose was adjusted to meet the vaginal restriction of < 68 Gy EQD2_{(α/β=3 Gy)} at 2 cm³. Late toxicity was prospectively assessed using RTOG scores for bladder and rectum, and the objective LENT-SOMA criteria for vagina.

Results

With a median follow-up of 31.0 months, no vaginal-cuff recurrences were found. Late toxicity: only 1G1(1.4%) rectal toxicity; 21G1(30.4%) and 3G2(4.3%) vaginal complications. Only one (1.4%) of 3 G2 manifested as vaginal shortening.

Conclusions

In postoperative EC patients treated with VBT, only one developed G2 vaginal stenosis with the use of 68 Gy EQD2_{(α/β=3 Gy)} as a dose constraint. These preliminary results seem to indicate the value of this dose limit for reducing G2 vaginal stenosis. Nonetheless, these findings should be confirmed in a larger number of patients with longer follow-up.

Consensus and recommendations on vaginal-cuff Brachytherapy of the Spanish Brachytherapy Groups of SEOR and SEFM

PURPOSE/OBJECTIVE(S)

On October 5, 2018, a meeting of the Spanish Society of Radiation Oncology (SEOR) Brachytherapy Group was held, in collaboration with the Spanish Society of Medical Physics (SEFM), with the aim of preparing a consensus document on postoperative vaginal-cuff brachytherapy (VCBT).

MATERIALS/METHODS

A survey including 42 questions was sent to Spanish Radiation Oncology Centres before the meeting. The survey items included: experience in VCBT, technique indications, previous patient preparation, applicator type, implant procedure, computerized tomography (CT) simulation, definition of target volumes and organs at risk (OAR), dose prescription, fractionation, treatment planning, dosimetric parameters and constraints to OAR. Thirty-three centres answered the survey. Statistical analysis of the survey considered that there was consensus when there was ≥ 85% of agreement related to a survey item, otherwise an item with < 85% of agreement would be discussed during the meeting to reach consensus.

RESULTS

The results of the survey are reported here. The mean number of patients treated per centre in 2017 was 52 ± 41 (range 7-175), and the mean number of procedures per centre was 175 ± 150 (range 24-701).There was consensus on: the indications, applicator type, the OAR to be considered, the prescription point, standardisation and dosimetric quality parameters. There was no consensus on: patient preparation for the implant, the need for performing CT simulation and the frequency, the length of the vagina to be treated, if CTV should be delimited, the definition of the clinical target volume, fractionation, overall EQD2, active source length, separation between dwelling stepping source positions, if considering the uniformity/maximum values for dwelling stepping sources, the optimization mode, and the limiting doses to the OAR. After presenting the results of the survey, the consensus meeting discussion focused on the issues for which there was no consensus.

CONCLUSION

A consensus document on postoperative VCBT of the Spanish Brachytherapy Groups of SEOR-SEFM was elaborated.